Abstract

Propionic acidaemia is caused by a deficiency of propionyl CoA carboxylase, an enzyme on the catabolic pathway of amino acids (isoleucine, valine, threonine and methionine) as well as cholesterol side chains, odd chain fatty acids and free propionate from the gut.

Treatment is aimed at reducing the sources of the precursors so patients are treated with a low protein diet and medicines - carnitine and metronidazole.

Decompensation is often triggered by metabolic stress such as febrile illness, particularly gastroenteritis, fasting, or constipation, but an obvious cause is not always apparent. Early signs of decompensation may be subtle: lethargy, even worse appetite than usual, xacerbation of pre-existing neurological signs (movement disorder etc). Vomiting is common and should always be taken seriously. Signs may be difficult to assess such as irritability, or just ‘not right’. Parents should always be listened to carefully..